The present invention relates to an oscillator which can make compact a temperature-compensated oscillator particularly used in the field of mobile communications by, e.g., a radio communication device or portable telephone, a manufacturing method therefor, and an oscillator.
Quartz oscillators each using, e.g., quartz crystal as a piezoelectric vibrator (piezoelectric component) are widely utilized in the field of data communications, information processing, and the like. Particularly, a potable terminal such as a portable telephone requires a frequency stability in a wide temperature range and a stability exceeding the obtained frequency to temperature characteristics.
Regarding this, a piezoelectric vibrator comprised of, e.g., quartz crystal, has temperature characteristics in that its frequency changes according to the ambient temperature. As an example of this, it is widely known that an AT-cut quartz vibrator has specific temperature characteristics in that the frequency varies largely in the high and low temperature sides with respect to a temperature near 25xc2x0 C. where the difference from the center frequency is the smallest. Therefore, in order to obtain the required characteristics described above, a temperature compensation circuit is generally added to a quartz oscillator so that stable operation can be obtained.
One temperature-compensated oscillator added with such a temperature compensation circuit has a container structure in which, as shown in, e.g., Japanese Patent Laid-Open Nos. 8-204452 and 9-167918, a container accommodating an oscillation circuit and a container accommodating a piezoelectric vibrator such as a quartz vibrator are integrally formed on the upper and lower sides of a substrate. As shown in FIG. 13a, an oscillator 1301 with this temperature compensation function has a container 1305 in which an accommodating portion 1305a for a piezoelectric vibrator 1302 and an accommodating portion 1305b for an electronic component 1303 constituting an oscillation circuit or the like are integrally formed in its upper and lower sides.
Although not shown, a predetermined circuit interconnection is formed on the bottom surface of the accommodating portion 1305a of the container 1305, and the piezoelectric vibrator 1302 is fixed to a predetermined portion of this circuit interconnection with a conductive adhesive or the like. In addition, a lid 1306a hermetically seals the interior of the accommodating portion 1305a. 
A predetermined circuit interconnection (not shown) is formed also on the bottom surface of the accommodating portion 1305b of the container 1305, and the electronic component 1303 is mounted at a predetermined portion of this circuit interconnection. A lid may be provided also to the accommodating portion 1305b of the electronic component 1303 in order to seal this region. Alternatively, a filler 1303a formed of a synthetic resin may fill the accommodating portion 1305b so that it covers and protects the electronic component 1303. In a temperature compensation type quartz oscillator shown in Japanese Patent Laid-Open No. 9-167918, an electronic component adjusting hole is formed in the lid of a container for the electronic component. The electronic component can be adjusted after a quartz oscillator is assembled and completed as well.
Also, another temperature-compensated oscillator has a container structure in which a container on which a substrate having an oscillation circuit is mounted and a container accommodating a piezoelectric vibrator are stacked on each other. As shown in FIG. 14, in an oscillator 1321 with this temperature compensation function, a container 1322 accommodating a piezoelectric vibrator and a container 1324 mounted with an electronic component 1323 constituting an oscillation circuit or the like are stacked on each other. The container 1324 has a recess. A predetermined circuit interconnection is formed at the bottom of this recess, and the electronic component 1323 is mounted at a predetermined portion of this circuit interconnection. A terminal of the circuit interconnection extends onto a bank surrounding the recess of the container 1324, so that it is electrically connected to the piezoelectric vibrator in the container 1322.
A portable terminal such as a portable telephone as described above requires downsizing and cost reduction as well as the frequency stability in a wide temperature range. Regarding these requirements, since the temperature-compensated oscillator with the arrangement of FIG. 13 needs a container for accommodating a piezoelectric vibrator and a container for accommodating an electronic component, it is difficult to downsize.
Since the temperature-compensated oscillator has an integral structure, if a trouble occurs in either one of the piezoelectric vibrator and electronic component, the entire temperature-compensated oscillator becomes defective. For this reason, even if no trouble occurs in the electronic component, since the piezoelectric vibrator is defective, the non-defective electronic component is treated as a defective one.
As shown in FIG. 13b, conventionally, sometimes the filler 1303a charged to fix the electronic component 1303 is attracted to the inner wall of the accommodating portion 1305b so it cannot completely cover the electronic component 1303. As described above, the conventional arrangement leads to a decrease in manufacturing yield and leads to an increase in product cost.
The present invention has been made to solve the above problems, and has as its object to downsize an oscillator to become smaller than a conventional one and to manufacture an oscillator at a lower cost than in the conventional case.
According to the present invention, in a container for an oscillation circuit which accommodates a piezoelectric vibrator, an oscillator comprises an electrode structure, that can be electrically connected, on the other surface of a multilayered substrate where a piezoelectric component is to be mounted, which opposes a side where the piezoelectric component is mounted, the electrode structure having a sufficient thickness.
According to the present invention, when the container for the oscillation circuit is mounted on another substrate through the electrode structure, a space is defined by the electrode structure between another substrate and the container for the oscillation circuit.
According to another embodiment of the present invention, in a container for an oscillator comprised of a piezoelectric vibrator and a plurality of semiconductor components, there is provided an oscillator in which the semiconductor components are mounted on the other surface of a multilayered substrate where the piezoelectric vibrator is to be mounted, which opposes a side where the piezoelectric component is mounted, a surface where the piezoelectric vibrator is mounted has a recessed structure, and the surface where the semiconductor components are mounted has an electrode structure that can be electrically connected to an external circuit mounting substrate when mounted thereon, the electrode structure having a thickness slightly larger than those of the semiconductor components.
According to the present invention, when the container for the oscillation circuit is mounted on another substrate through the electrode structure, the semiconductor component is placed in a space defined by the electrode structure between another substrate and the container for the oscillation circuit.
According to the present invention, in an oscillator comprised of a piezoelectric vibrator and a plurality of semiconductor components, the semiconductor components are mounted on the other surface of a multilayered substrate, where the piezoelectric vibrator is to be mounted, which opposes a side where the piezoelectric component is to be mounted, a surface where the piezoelectric vibrator is mounted has a recessed structure, and the surface where the semiconductor components are mounted has an electrode structure that can be electrically connected to an external circuit mounting substrate when mounted thereon, the electrode structure having a thickness slightly larger than those of the semiconductor components.
According to the present invention, when the oscillator is mounted on another substrate through the electrode structure, the semiconductor component is placed in a space defined by the electrode structure between another substrate and the container for the oscillation circuit.
According to embodiment of the present invention, in an oscillator comprised of a piezoelectric vibrator and an electronic component, a substrate on which the electronic component is mounted is adhered to a bottom surface of the piezoelectric vibrator and is integrated therewith, and a conduction electrode which electrically connects the piezoelectric vibrator and the substrate where the electronic component is to be mounted constitutes an oscillator.
According to the present invention, when the oscillator is mounted on another substrate through the electrode structure, the semiconductor component is placed in a space defined by the electrode structure between another substrate and the container for the oscillation circuit.
In the present invention, the electronic component is arranged on the substrate which is in contact with the bottom surface of the piezoelectric vibrator.
In an oscillator according to still another embodiment of the present invention and comprised of a piezoelectric vibrator and an electronic component, a substrate on which the electronic component is mounted is arranged on a bottom surface of the piezoelectric vibrator, and the piezoelectric vibrator and the substrate are integrated through a conduction electrode that electrically connects the piezoelectric vibrator and the substrate to each other, thereby forming an oscillator.
According to the present invention, the electronic component is arranged between the substrate and the bottom surface of the piezoelectric vibrator.
According to the present invention, the electronic component is arranged on a surface of a circuit substrate where the oscillator is to be mounted.
According to still another embodiment of the present invention, in a laminated container comprised of at least two multilevel structure substrates, in which at least one of multilevel laminated substrates with recesses, on an upper and lower surfaces thereof, at portions where an electronic component and a piezoelectric component are to be mounted, employs an annular laminated substrate, the annular laminated substrate is in contact with at least one flat laminated substrate which constitutes the laminated container, and one layer which opposes the flat laminated substrate in contact therewith is the annular laminated substrate, there is provided an oscillator, wherein portions corresponding to vertical and horizontal sizes of an inner wall of the recess constituting the laminated container and a portion corresponding to a vertical size of an inner wall of the other annular recess are located on the same line by not less than 60%.
According to still another embodiment of the present invention, in a laminated container is comprised of at least two multilevel laminated substrates, in which one of the multilevel laminated substrates employs an annular laminated substrate so as to form a recess at a portion thereof where an electronic component and a piezoelectric component are to be mounted, the annular laminated substrate is in contact with at least one flat laminated substrate constituting the laminated container, and at least one layer which is in contact with the flat laminated structure is a laminated substrate with pedestal portions arranged at corners thereof, there is provided an oscillator, wherein vertical and horizontal sizes of four corners of an inner wall of the annular recess constituting the laminated container and an inner size of each corner portion of the other pedestal portion of the flat laminated substrate are located on the same line.
According to an oscillator manufacturing method of the present invention, there is provided a method of manufacturing a container for a surface-mounted oscillation circuit, comprising, in order to form a pedestal portion with a sufficiently large thickness on the other surface of a substrate where a piezoelectric component is to be mounted, which opposes a side where the piezoelectric component is mounted, the steps of arranging a positioning plate, fitting a conductive pedestal portion in the positioning plate, and integrating and heating the substrate, the positioning plate, and the conductive pedestal portion.
According to a piezoelectric component manufacturing method of the present invention, there is provided a method of manufacturing a container for a surface-mounted oscillation circuit, comprising, in order to form a pedestal portion with a sufficiently large thickness on a surface of a substrate where a piezoelectric component is to be mounted, which opposes a side where the piezoelectric component is mounted, the steps of arranging a conductive pedestal portion mask, printing a conductive pedestal portion through the conductive pedestal portion mask, and heating the conductive pedestal portion.
According to the present invention, an electronic component is mounted on that surface of the container for an oscillation circuit which opposes a surface where the piezoelectric component is mounted, thereby forming an oscillator.
According to still another embodiment of the present invention, an oscillator comprises a hermetically sealable container arranged on a major surface of a substrate and adapted to accommodate a piezoelectric vibrator, and a plurality of electrode structures arranged on a lower surface of the substrate and higher than a semiconductor component to be flip-chip mounted on the lower surface of the substrate, wherein the piezoelectric vibrator, the semiconductor component, and the electrode structures constitute an oscillation circuit.
According to the present invention, the plurality of electrode structures serve as columns for forming a heat dissipation space around the semiconductor component which is flip-chip mounted. The semiconductor component does not come into contact with another member with which the distal ends of the electrode structures come into contact.
In the present invention described above, the container may be constituted by a frame formed on the major surface of the substrate and a lid formed on the frame, or by a recess formed in the major surface of the substrate and a lid covering the recess. Also, the substrate may have a multilayered interconnection structure.
In the present invention, the substrate may be formed of a first substrate where the container is to be formed, and a second substrate where the semiconductor component is mounted. The semiconductor component performs temperature compensation of an oscillation frequency obtained by the piezoelectric vibrator.
According to still another embodiment of the present invention, there is provided an oscillator comprising a piezoelectric vibrator arranged on a major surface of a substrate to be disconnected from an outer air, a semiconductor substrate flip-chip mounted on a lower surface of the substrate, and a plurality of electrode structures arranged on the lower surface of the substrate and higher than the semiconductor component, wherein the piezoelectric vibrator, the semiconductor component, and the electrode structures constitute an oscillation circuit.
According to the present invention, the plurality of electrode structures serve as columns for forming a heat dissipation space around the semiconductor component which is flip-chip mounted. The semiconductor component does not come into contact with another member with which the distal ends of the electrode structures come into contact.
According to the present invention, the container may be constituted by a frame formed on the major surface of the substrate and a lid formed on the frame, or by a recess formed on the major surface of the substrate and a lid covering the recess. The substrate may have a multilayered interconnection structure.
According to the present invention, the substrate may be formed of a first substrate where the container is to be formed, and a second substrate where the semiconductor component is mounted. The semiconductor component performs temperature compensation of an oscillation frequency obtained by the piezoelectric vibrator.
A container for an oscillation circuit using a piezoelectric vibrator according to the present invention comprises a hermetically sealable container arranged on a major surface of a substrate and adapted to accommodate a piezoelectric vibrator, and a frame stacked on a lower surface of the substrate and higher than a semiconductor component to be flip-chip mounted on the lower surface of the substrate, wherein a shift amount between the substrate and the frame in a widthwise direction of the frame is less than 40% a width of the frame, and the piezoelectric vibrator, the semiconductor component, and the electrode structure constitute an oscillation circuit.
A container for an oscillation circuit using a piezoelectric vibrator according to the present invention comprises a hermetically sealable container arranged on a major surface of a substrate and adapted to accommodate a piezoelectric vibrator, and four pedestal portions arranged in contact with four corners of a lower surface of the substrate and higher than a semiconductor component to be flip-chip mounted on the lower surface of the substrate, wherein a shift amount between the substrate and the frame in a widthwise direction of the frame is less than 40% a width of the frame, positions of four sides of a rectangle inscribed to the four pedestal portions overlap positions where four inner sides of the frame are projected toward the substrate, and the piezoelectric vibrator, the semiconductor component, and the electrode structure constitute an oscillation circuit.
A container for an oscillation circuit using a piezoelectric vibrator according to the present invention comprises a hermetically sealable container arranged on a major surface of a substrate and adapted to accommodate a piezoelectric vibrator, and four pedestal portions arranged in contact with four corners of a lower surface of the substrate and higher than a semiconductor component to be flip-chip mounted on a lower surface of the substrate, wherein a shift amount between the substrate and the frame in a widthwise direction of the frame is less than 40% a width of the frame, positions of four sides of a rectangle inscribed to the four pedestal portions overlap positions where four inner sides of the frame are projected toward the substrate within a region of 2 mm, and the piezoelectric vibrator, the semiconductor component, and the electrode structure constitute an oscillation circuit.